In general, filter dust collectors are installed on equipments, such as a boiler and an incinerator, which generate dust, installed inside a flour mill, a feed manufacturing factory, a cement manufacturing factory, or the likes. The installed filter dust collectors collect particle type materials such as dust, unburned carbon, and the likes, and remove or recover the collected particles.
For instance, as shown in FIG. 1, a conventional dust collector includes a dust collector body 100 having a cover 105, an intermediate plate 112 formed in a longitudinal direction inside the dust collector body 100, and a number of filter bags 110 formed along the longitudinal direction of the dust collector body 100 from the lower portion of the intermediate plate 112. Furthermore, a number of venturi tubes 115 corresponding to the filter bags 110 are mounted on the upper portion of the intermediate plate 112.
Nozzle pipes 120 are arranged above the venturi tubes 115 in parallel with the intermediate plate 112. A number of solenoid valves 130 are mounted on ends of the nozzle pipes 120 exposed to the outside of the dust collector body 100, and a compressed air tank 140 is mounted on the outer surfaces of the nozzle pipes 120. Furthermore, a timer (or time kit) 150 is mounted on the outer surface of the dust collector 100.
The dust collector shown in FIG. 1 usually uses high-pressure compressed air of 5˜6 kgf/cm2 as pulse air, but cleaning effect is not sufficient due to weak pulse. Therefore, designing engineer should apply very low air-to-cloth ratio, and so, the dust collector gets bigger due to increase of the number of the filter bags 110. Moreover, the conventional dust collector has a disadvantage in that the filter bags 110 are quickly blocked since condensed water and oil are mixed with the high-pressure compressed air used for generating pulse.
Meanwhile, a dust collector using very low pressure air (0.5 kgf/cm2) to generate pulse is also disclosed. As shown in FIG. 2, the dust collector includes a number of filter bags 210 attached on an intermediate plate within a dust collector body 200 in a longitudinal direction, an air inlet 220 formed in an area of the outer surface of the dust collector body 200 to introduce the air, an air outlet 230 formed in the other area of the dust collector body 200 to discharge filtered air, and a compressed air tank 250 disposed inside a machine room 205 located above the filter bags 210, differently from the dust collector shown in FIG. 1.
The compressed air tank 250 has nozzles 260 of the same number as the filter bags 110 to pass the compressed air tank 250 vertically, and diaphragm valves 270 are mounted on the upper end of each nozzles 260. The compressed air tank 250 is connected with a compressed air source (a ring blower, a roots blower or air decompressed by a pressure reducing valve) and with a safety valve 240.
In this way, excellent cleaning effect can be obtained by generating very strong pulses with low pressure air (0.5 kgf/cm2) having less condensed water and oil. However, the conventional low pressure pulse type dust collector has several disadvantages in that it requires a lot of very expensive components and increases manufacturing costs and maintenance fees because it needs one nozzle and one diaphragm valve for each filter bag and the plurality of solenoid valves (not shown, and ⅓˜¼ of the number of the filter bags 210) are needed to generate a pulse by group of three or four diaphragm valves 270, the timer (or time kit, not shown) to send signal to the solenoid valves to control pulsing interval must be mounted.